Fluid heater

ABSTRACT

A fluid heater has a fluid pipe through which a fluid flows. A radiant heating element is enclosed in a quartz mantle. The fluid pipe is concentrically arranged about the quartz mantle. A first temperature sensor is positioned at a section of the outer circumference of the fluid pipe opposite the heating element.

BACKGROUND OF THE INVENTION

The present invention relates to a fluid heater including a pipe throughwhich a fluid flows.

It is known to heat liquid and gasses in order to vaporize them or topressurize them. The known devices, however, have a slow response time.It takes a relatively long time to heat the fluid to be heated afterswitching on the heater, and after switching off the heater heating ofthe fluid is not immediately ended.

From German Patent Application 44 20 493 a fluid heater of theaforementioned kind is known in which the heating elements are electricresistance bands applied to the outer circumference of the fluid pipe.Due to the indirect heating of the fluid through the pipe wall, a fastswitching on and off of the heater without delay of the heating actionand of the shutdown of the heating action for the fluid is not possible.

From the documents German Gebrauchsmuster 19 06 191, GermanGebrauchsmuster 89 13 683, German Patent 38 41 448 and German publisheddocument 12 69 748, heating elements and radiant heaters are knownwhich, however, are not designed for heating a fluid flowing through apipe and are also not suitable for this purpose.

The object of the present invention is to provide a fluid heater whichcan be manufactured inexpensively and which provides for a fastswitching on and switching off of the heater.

SUMMARY OF THE INVENTION

The inventive object is solved by a fluid heater such that the pipe isarranged concentrically about a radiant heater enclosed by a quartzmantle.

A special advantage of the present invention is that the quartz mantleonly retains minimal heat so that directly after switching off the fluidheater the fluid is no longer being heated.

According to a preferred embodiment of the invention, the quartz mantleis a quartz tube that contains the radiant heater in the form of anelectrical heating element. Preferably, at least a section of the quartztube contains a heating wire. When a plurality of sections of the quartztube contain a heating element, switching together of multiple heatingelements provides an increased heating output.

According to a further preferred embodiment of the invention, a safetytemperature sensor is provided at a section of the outer circumferenceof the fluid pipe positioned opposite of the section of the quartz tube.Preferably, the heating current flowing through the heating wire isswitched off when the safety temperature sensor measures a temperaturesurpassing a predetermined temperature value. The temperature valueprovided by the safety temperature sensor furthermore shows whether gasflows through the fluid pipe because in this case the heating energy istransported by the fluid medium to the section of the outercircumference of the fluid pipe

According to a further preferred embodiment of the invention, a secondtemperature sensor is provided at the outlet of the fluid pipe.Advantageously, the temperature value determined by the secondtemperature sensor is used for controlling the heating output.

Advantageously, the radiant heater is an infrared heater and the fluidpipe consists of stainless steel, a ceramic pipe, or a steel pipe thatis lined with a ceramic material or a ceramic tube. With thisembodiment, a large portion of the emitted heat energy coming from theradiant heater is reflected at the inner circumference of the fluid pipeinto the fluid pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention as well as further advantages and embodiments thereof willbe explained in the following with the description of particularembodiments with the aid of the drawings. It is shown in:

FIG. 1 a schematic representation of a first embodiment of the inventivefluid heater; and

FIG. 2 a cross-sectional view of a second embodiment of the inventivefluid heater.

In the drawings, the same reference numerals indicate identical orcorresponding elements.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

In FIG. 1 a first embodiment of the inventive fluid heater isschematically represented. The fluid heater 1 has a fluid pipe 2 inwhich a non-represented gas flows, whereby the flow direction isindicated by arrows in FIG. 1. In the fluid pipe 2 a quartz tube 3 isconcentrically arranged that includes a heating wire 4. The heating wire4 has two supply wires 5, 6 which are guided through openings in thequartz pipe 3 and the fluid pipe 2 to the exterior. By suppling avoltage to the supply wires 5, 6, the heating wire 4 is supplied withenergy and radiates especially infrared heat that heats in a continuousflow method the gas flowing in the direction of the arrows.

A safety temperature sensor 7 senses the temperature at the outer sideof the quartz mantle 3 in order to switch off the current to the heaterwhen the temperature limit is surpassed. A second temperature sensor 8senses the temperature of the gas downstream of the fluid heater 1 in ananalog manner. The value of the temperature measured by the secondtemperature sensor 8 can be used for controlling the electrical outputsupplied to the heating wire 4 via the supply wires 5, 6 in order tomaintain the temperature of the gas constant.

In FIG. 2 a cross-sectional view of a second embodiment of the presentinvention is represented. The fluid heater 1 has a fluid pipe 2 ofpolished stainless steel in which a non-represented gas, for example,nitrogen gas, flows. The flow direction is indicated by arrows. The gasenters through an inlet 9 arranged transverse to the fluid pipe 2 intothe pipe 2 and exits through outlet 10 extending transverse to the fluidpipe 2 and rotated by 90° relative to the inlet 9. In the fluid pipe 2 aquartz mantle is axially symmetrically arranged which is embodied as aquartz tube 3 extending past the inlet 9 and the outlet 10. In thequartz tube 3 a non-represented heating wire is arranged extending alongthe schematically indicated length L within a section 11 of the quartzmantle 3. Supply wires 5, 6 are provided via which electrical voltage issupplied in order to heat the heating wire. In contrast to theembodiment represented in FIG. 1, the supply wires 5, 6 are guidedwithin the quartz tube 3 and are guided through the ends of the quartzpipe out of the fluid pipe 2. The locations at which the quartz tube 3exits from the fluid pipe 2 are provided with sealing devices 12, 13 atthe inlet side 9, respectively, the outlet side 10 which are preferablyembodied as sealing rings or gaskets. The safety temperature sensor 7senses the temperature at the outer circumference of the fluid pipe 2. Asecond temperature sensor 8 senses, downstream of the heated section 11of the quartz pipe 3 at the outer circumference of the tube guiding thefluid, the gas temperature.

The invention has been described with the aid of two preferredembodiments. However, to a person skilled in the art numerous variationsand developments are obvious without deviating from the gist of theinvention. For example, instead of a gas a liquid can be heated by theinventive heater.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

What is claimed is:
 1. A fluid heater (1) comprising: a fluid pipe (2)through which a fluid flows; a radiant heating element (4); a quartzmantle (3) enclosing said radiant heating element (4); said fluid pipe(2) concentrically arranged about said quartz mantle (3); a firsttemperature sensor (7) positioned at a section of an outer circumferenceof said fluid pipe (2) opposite said heating element (4); and a secondtemperature sensor (8) positioned at an outlet (10) of said fluid pipe(2), wherein a temperature determined by said second temperature sensor(8) is used for controlling heating output of said heater.
 2. A heateraccording to claim 1, wherein a heating current flowing through saidheating element (4) is switched off when a temperature measured bytemperature sensor (7) surpasses a predetermined temperature value.
 3. Aheater according to claim 1, wherein said heating element (4) is aninfrared radiant heater.
 4. A heater according to claim 1, wherein saidheating element (4) is an electrical heating element.
 5. A heateraccording to claim 1, wherein said heating element (4) is a heatingwire.
 6. A heater according to claim 1, wherein said quartz mantle is aquartz tube (3) that contains said heating element (4).
 7. A heateraccording to claim 6, wherein said heating element (4) has supply wires(5, 6) guided to the exterior of said heater through at least one end ofsaid quartz tube (3).
 8. A heater according to claim 6, wherein saidheating element (4) has supply wires (5, 6) guided to the exterior ofsaid heater through at least one opening in the wall of said quartz tube(3).
 9. A heater according to claim 6, wherein said heating element (4)is a heating wire contained in at least one section (11) of said quartztube (3).
 10. A heater according to claim 1, wherein a plurality of saidheating elements (4) are provided.
 11. A heater according to claim 1,wherein said fluid pipe (2) consists of stainless steel.
 12. A heateraccording to claim 1, wherein said fluid pipe (2) consists of ceramic.13. A heater according to claim 1, wherein said fluid pipe (2) is asteel pipe lined with ceramic.
 14. A heater according to claim 1,wherein the fluid is a gas, preferably nitrogen.